import { useEffect, useState } from 'react'
import { Button, Card, Col, Container, Form, Row } from 'react-bootstrap'
import { Link, useParams } from 'react-router-dom'
import { createThread, getCategory, listThreadsByCategory } from '../api/client'
import { useAuth } from '../context/AuthContext'

export default function CategoryView() {
  const { id } = useParams()
  const { token } = useAuth()
  const [category, setCategory] = useState(null)
  const [threads, setThreads] = useState([])
  const [error, setError] = useState('')
  const [loading, setLoading] = useState(true)
  const [title, setTitle] = useState('')
  const [body, setBody] = useState('')
  const [saving, setSaving] = useState(false)

  useEffect(() => {
    setLoading(true)
    Promise.all([getCategory(id), listThreadsByCategory(id)])
      .then(([categoryData, threadData]) => {
        setCategory(categoryData)
        setThreads(threadData)
      })
      .catch((err) => setError(err.message))
      .finally(() => setLoading(false))
  }, [id])

  const handleSubmit = async (event) => {
    event.preventDefault()
    setSaving(true)
    setError('')
    try {
      await createThread({ title, body, categoryId: id })
      setTitle('')
      setBody('')
      const updated = await listThreadsByCategory(id)
      setThreads(updated)
    } catch (err) {
      setError(err.message)
    } finally {
      setSaving(false)
    }
  }

  return (
    <Container className="py-5">
      {loading && <p className="bb-muted">Loading category...</p>}
      {error && <p className="text-danger">{error}</p>}
      {category && (
        <>
          <div className="bb-hero mb-4">
            <p className="bb-chip">Category</p>
            <h2 className="mt-3">{category.name}</h2>
            <p className="bb-muted mb-0">
              {category.description || 'No description added yet.'}
            </p>
          </div>

          <Row className="g-4">
            <Col lg={7}>
              <h4 className="bb-section-title mb-3">Threads</h4>
              {threads.length === 0 && (
                <p className="bb-muted">No threads here yet. Start one below.</p>
              )}
              {threads.map((thread) => (
                <Card className="bb-card mb-3" key={thread.id}>
                  <Card.Body>
                    <Card.Title>{thread.title}</Card.Title>
                    <Card.Text className="bb-muted">
                      {thread.body.length > 160 ? `${thread.body.slice(0, 160)}...` : thread.body}
                    </Card.Text>
                    <Link to={`/thread/${thread.id}`} className="stretched-link">
                      View thread
                    </Link>
                  </Card.Body>
                </Card>
              ))}
            </Col>
            <Col lg={5}>
              <h4 className="bb-section-title mb-3">Start a thread</h4>
              <div className="bb-form">
                {!token && (
                  <p className="bb-muted mb-3">Log in to create a new thread.</p>
                )}
                <Form onSubmit={handleSubmit}>
                  <Form.Group className="mb-3">
                    <Form.Label>Title</Form.Label>
                    <Form.Control
                      type="text"
                      placeholder="Topic headline"
                      value={title}
                      onChange={(event) => setTitle(event.target.value)}
                      disabled={!token || saving}
                      required
                    />
                  </Form.Group>
                  <Form.Group className="mb-3">
                    <Form.Label>Body</Form.Label>
                    <Form.Control
                      as="textarea"
                      rows={5}
                      placeholder="Share the context and your question."
                      value={body}
                      onChange={(event) => setBody(event.target.value)}
                      disabled={!token || saving}
                      required
                    />
                  </Form.Group>
                  <Button type="submit" variant="dark" disabled={!token || saving}>
                    {saving ? 'Posting...' : 'Create thread'}
                  </Button>
                </Form>
              </div>
            </Col>
          </Row>
        </>
      )}
    </Container>
  )
}